CN114114652A

CN114114652A - Imaging lens and imaging device

Info

Publication number: CN114114652A
Application number: CN202110629648.5A
Authority: CN
Inventors: 野田隆行; 中井正刚; 布施慎吾
Original assignee: Tamron Co Ltd
Current assignee: Tamron Co Ltd
Priority date: 2020-08-31
Filing date: 2021-06-07
Publication date: 2022-03-01
Also published as: JP2022040489A

Abstract

The problem is to reduce the weight and cost by including a resin lens, and to suppress the change of the angle of field due to the change of the atmospheric temperature. The imaging lens is composed of N lenses including a 1 st lens (L1) having a concave image side, a 2 nd lens (L2) having a concave object side, and an N th lens (5 < N < 10) disposed closest to the image side, wherein N is greater than or equal to 5 and less than or equal to 10, the 1 st group is located closer to the object side than a stop S, and the 2 nd group is located closer to the image side than the stop S, the 2 nd group includes a lens (Gp) having a refractive index (N) of N < 1.68 corresponding to a d-line and an Abbe number (V) of 16 < V < 31 corresponding to the d-line, and a lens (Lp) disposed adjacent to the lens (Gp) is a resin lens (Lp), and the imaging lens satisfies a predetermined condition. An imaging device provided with the imaging lens is also provided.

Description

Imaging lens and imaging device

Technical Field

The invention relates to an imaging lens and an imaging apparatus.

Background

In recent years, various small-sized imaging devices using a solid-state imaging element, such as a digital camera, have been widely used. Further, an imaging optical system of a small imaging device is also required to be further reduced in size and weight and to be reduced in cost. In an on-vehicle lens, a lens for an unmanned aerial vehicle (a small unmanned aerial vehicle, an unmanned aerial vehicle), and the like, a part thereof is configured by using a resin lens in order to achieve weight reduction and cost reduction.

For example, in example 3 of patent document 1, an imaging lens is proposed which is composed of 6 lenses including negative positive, positive negative, positive resin lenses in order from the object side and has a field angle of 100 °.

In example 22 of patent document 2, an imaging lens is proposed which is composed of 6 lenses including negative positive, positive negative, positive, and resin lenses in this order from the object side and has a field angle of 98 °. In these imaging lenses, a wide angle of view is achieved, and high optical performance is maintained in a normal temperature environment.

Prior art documents

Patent document

[ patent document 1] Japanese patent laid-open publication No. 2018-136583

[ patent document 2] Japanese patent laid-open No. 2016-65954

Disclosure of Invention

Problems to be solved by the invention

However, in the imaging lens disclosed in patent document 1, when the incident angle is 80 °, the field angle varies by-0.383 ° at 125 ℃ and the field angle varies by 0.158 ° at-20 °, compared to the normal temperature environment (20 ℃). In the imaging lens disclosed in patent document 2, there is a variation in the angle of view of-0.390 ° at 125 ℃, and a variation in the angle of view of 0.157 ° at-20 °. In this way, in these imaging lenses, the variation in the angle of view due to the temperature change is not sufficiently suppressed.

Accordingly, an object of the present invention is to provide an imaging lens and an imaging apparatus that include a resin lens, thereby reducing weight and cost, and that can suppress a change in angle of view due to a change in ambient temperature.

Means for solving the problems

In order to solve the above problem, an imaging lens according to the present invention is an imaging lens including N lenses including a 1 st lens and a 2 nd lens, which are concave on an image side and concave on an object side, and an nth lens having positive refractive power disposed closest to the image side in this order from the object side, wherein 6 ≦ N ≦ 10, an aperture stop is disposed between the 1 st lens and the nth lens, the aperture stop is disposed on the object side as a 1 st group, and the image side of the aperture stop is disposed as a 2 nd group, the 2 nd group includes a lens Gp having a refractive index N corresponding to a d-line of N < 1.68 and an abbe number V corresponding to the d-line of 16 < V < 31, and a lens disposed adjacent to the lens Gp is a resin lens Lp, and the imaging lens satisfies the following conditions:

-0.59＜f/fp＜-0.01·····(1)

wherein the content of the first and second substances,

f: the focal length of the imaging lens

fp: the combined focal length of the lens Gp and the lens Lp.

In order to solve the above problem, an imaging lens according to the present invention is an imaging lens including N lenses including a 1 st lens and a 2 nd lens, the 1 st lens and the 2 nd lens being concave on an object side and being concave on an image side in this order from the object side, and an nth lens disposed closest to the image side, where N is 5, an aperture stop is disposed between the 1 st lens and the nth lens, a 1 st group is disposed on an object side of the aperture stop, and a 2 nd group is disposed on an image side of the aperture stop, the 2 nd group includes a lens Gp having a refractive index N corresponding to a d-line of N < 1.68 and an abbe number V corresponding to the d-line of 16 < V < 31, and a lens disposed adjacent to the lens Gp is a lens Lp made of resin, the imaging lens satisfying the following conditions:

-0.59＜f/fp＜-0.01·····(1)

wherein the content of the first and second substances,

f: the focal length of the imaging lens

fp: the combined focal length of the lens Gp and the lens Lp.

In order to solve the above problem, an imaging device according to the present invention includes the imaging lens and an imaging element that converts an optical image formed by the imaging lens into an electrical signal.

Effects of the invention

According to the present invention, the inclusion of the resin lens enables weight reduction and cost reduction, and also enables suppression of a change in the angle of field due to a change in the ambient temperature.

Drawings

Fig. 1 is a sectional view of an imaging lens of embodiment 1.

Fig. 2 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 1.

Fig. 3 is a sectional view of an imaging lens of embodiment 2.

Fig. 4 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 2.

Fig. 5 is a sectional view of an imaging lens of embodiment 3.

Fig. 6 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 3.

Fig. 7 is a sectional view of an imaging lens of embodiment 4.

Fig. 8 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 4.

Fig. 9 is a sectional view of an imaging lens of embodiment 5.

Fig. 10 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 5.

Fig. 11 is a sectional view of an imaging lens of embodiment 6.

Fig. 12 is an aberration diagram in an infinity focusing state of the imaging lens of embodiment 6.

Fig. 13 is a sectional view of an imaging lens of embodiment 7.

Fig. 14 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 7.

Fig. 15 is a sectional view of an imaging lens of embodiment 8.

Fig. 16 is an aberration diagram in an infinity focus state of the imaging lens of embodiment 8.

Description of the reference numerals

L1. 1 st lens

L2. 2 nd lens

L3. 3 rd lens

L4. th lens

L5. th lens No. 5

L6. th lens No. 6

L7. th lens

L8. 8 th lens

L9. th lens

L10. th lens

CG protective glass

IMG image plane

IRCF infrared cut-off filter

Detailed Description

Embodiments of an imaging lens and an imaging apparatus according to the present invention are described below. The imaging lens and the imaging apparatus described below are one embodiment of the imaging lens and the imaging apparatus according to the present invention, and the imaging lens and the imaging apparatus according to the present invention are not limited to the following embodiment.

1. Imaging lens

1-1. optical construction

The optical configuration of the imaging lens will be described. The imaging lens is substantially composed of n lenses, wherein the n lenses comprise a 1 st lens with a concave object side, a 2 nd lens with a concave object side and an n lens arranged at the most image side in sequence from the object side, and n is more than or equal to 5 and less than or equal to 10. Here, "substantially constituted by … …" means that the optical elements substantially constituting the imaging lens are n lenses, i.e., the 1 st lens to the n-th lens, but it is permissible to further include optical elements other than a lens having no substantial optical power, a lens such as an aperture stop, a cover glass, and the like. When the imaging lens includes an aperture stop between the 1 st lens and the n-th lens, and the 1 st group is a 1 st group on the object side of the aperture stop and the 2 nd group is a 2 nd group on the image side of the aperture stop, the 1 st group includes the 1 st lens and the 2 nd lens, and the 2 nd group includes a lens Gp and a lens Lp, which will be described later, and the n-th lens.

1-1-1. lens construction

(1) No. 1 lens and No. 2 lens

By arranging the 1 st lens whose image side is concave and the 2 nd lens whose object side is concave in this order on the object side of the imaging lens, a wide angle of view can be achieved, and the front lens diameter is reduced compared to the angle of view. Here, "the number of pixels on the image pickup device per 1 degree of the imaging angle of view" is defined as "angular resolution". By disposing the 1 st lens and the 2 nd lens having the surface shapes as described above on the object side of the imaging lens, it is easy to obtain an imaging lens having a higher angular resolution in the vicinity of the optical axis than in the periphery. By increasing the angular resolution in the vicinity of the optical axis compared to the periphery, it is possible to form an image with high resolution for an object in the vicinity of the optical axis, and to capture an image with a wider range for the periphery. Therefore, if the imaging lens is applied to, for example, an in-vehicle camera, an unmanned aerial vehicle camera, or the like, and is mainly used as a sensor camera, it is possible to detect a distant object with high accuracy in front of a moving object such as a vehicle or an unmanned aerial vehicle in the traveling direction, and recognize an object (an obstacle, a traffic light, a road traffic sign, or the like) around the moving object in a wide range. The vicinity of the optical axis is a range around 2 degrees higher than the image height including the center of the optical axis, and the periphery is a range outside a range around 7 degrees higher than the image height including the center of the optical axis.

In addition, in a lens having a wide angle of view, the incident height (distance of the incident position from the optical axis) of the principal ray to the peripheral image height (for example, 10 images, 7 images, and the like) is the largest in the 1 st lens. Thus, by making the image side of the 1 st lens concave and increasing the curvature thereof as described above, coma can be corrected well from the vicinity of the center of the optical axis to the periphery, and distortion aberration in the periphery can be made to fall within an appropriate range.

In order to obtain these effects and effects, the 1 st lens is preferably an uneven shape with the concave surface facing the image side. Further, the 2 nd lens is preferably a concave-convex shape having a concave surface facing the object side. In addition, the 1 st lens having negative power is preferable in obtaining an optical configuration of a negative first type. When the 1 st group is composed of 2 lenses, i.e., the 1 st lens and the 2 nd lens, the 2 nd lens preferably has positive refractive power.

(2) Lens Gp and lens Lp

In the imaging lens, the lens Gp is a lens having a refractive index N corresponding to the d-line of N < 1.68 and an abbe number V corresponding to the d-line of 16 < V < 31 among the lenses constituting the group 2.

The lens material satisfying the above conditions is currently a resin material. That is, the lens Gp is basically a resin lens. The resin material has a larger thermal expansion coefficient than the glass material. Therefore, if the imaging lens is configured by using a resin lens, the refractive index changes with changes in the ambient temperature, and the surface shape and the thickness of the lens also change, so that the field angle changes and the focal position also easily changes. However, in this imaging lens, by providing the surface shapes of the 1 st lens and the 2 nd lens as described above and disposing the lens Gp in the 2 nd group on the image side of the stop, it is possible to suppress variation in the incident height of the principal ray in the lens Gp to the peripheral image height and accompanying changes in the ambient temperature. Therefore, since the variation in the incident height of the principal ray to the peripheral image height in the lens Gp is small, even if the refractive index, surface shape, or the like of the lens Gp changes due to the ambient temperature, the influence of the variation in the field angle can be reduced, and the variation in the focal position can be suppressed.

In the imaging lens, a lens disposed adjacent to the lens Gp is a resin lens Lp. The lens Lp may be a resin lens, and may be disposed on the object side of the lens Gp, on the image side of the lens Gp, or on both sides thereof. By disposing the lens Lp adjacent to the lens Gp and satisfying the conditional expression (1) described later, the variation in the field angle can be suppressed in a wide temperature range. For example, a vehicle-mounted lens, an unmanned aerial vehicle lens, or the like is often used outdoors, and is often used at temperatures below freezing to high temperatures. By disposing the lens Lp adjacent to the lens Gp, for example, the sign, surface shape, and the like of the refractive powers of both lenses are appropriately adjusted, whereby it is easy to linearly cancel out the change in the field angle and the change in the focal position due to the change in the ambient temperature. Therefore, at least 2 of the lenses constituting the imaging lens can be resin lenses (lens Gp, lens Lp), and an imaging lens with a small change in angle of view even when the ambient temperature changes can be realized. In order to obtain these effects, the lens Lp is more preferably disposed on the object side of the lens Gp.

By providing the lens Gp and the lens Lp with lenses having powers of different signs, it is possible to easily cancel out the change in the field angle and the change in the focal position due to the change in the atmospheric temperature linearly, and it is also preferable in terms of correcting chromatic aberration. At this time, it is preferable that the lens Gp have negative power and the lens Lp have positive power in terms of correcting chromatic aberration well. Further, it is preferable that the lens Gp is a biconcave lens and the lens Lp is a biconvex lens. By providing the lens Gp and the lens Lp as a biconcave lens and a biconvex lens, respectively, it is possible to prevent an excessively large curvature of the lens surface while arranging each lens with a strong refractive power, to correct chromatic aberration well, and to suppress the occurrence of other aberrations.

The air gap between the lens Gp and the lens Lp is preferably smaller than the center thickness of the lens Gp or the lens Lp. If the air space between the lens Gp and the lens Lp is reduced, the effect of shortening the total optical length of the imaging lens can be obtained. Further, the air gap between the lens Gp and the lens Lp is small, and the field angle variation and the aberrations can be more effectively cancelled. Therefore, by reducing the air gap, the lens Gp and the lens Lp can be more efficiently offset by appropriately arranging appropriate optical power, surface shape, and the like for the change in the field angle associated with the change in the ambient temperature.

Further, the lens Gp and the lens Lp preferably abut against each other at peripheral portions (edge portions). By bringing the lens Gp and the lens Lp into contact with each other at the peripheral portion, the air gap is reduced, and an eccentricity error that is likely to occur when the total optical length is shortened can be reduced as compared with a case where both lenses are arranged apart from each other. In addition, in the case where the two lenses are arranged apart from each other, if the air gap between the two lenses is made smaller, it is difficult to set the air gap with high accuracy when the lenses are mounted. On the other hand, if both lenses are brought into contact with each other at the peripheral portion, it is possible to suppress the occurrence of an eccentricity error or an air gap error, and to reduce various manufacturing errors. Therefore, a lens having excellent optical performance can be manufactured with high yield.

(3) N-th lens

The nth lens is a lens disposed closest to the image side in the imaging lens. When n is 5, the power of the nth lens arrangement is not particularly limited, but is preferably negative, for example. On the other hand, the nth lens is set to have positive power at 6 ≦ n. When n is 6. ltoreq.n, by arranging a positive refractive power for the n-th lens, vignetting that tends to occur when a wide angle of view is achieved can be suppressed, and a decrease in the amount of peripheral light can be suppressed.

Further, the shape of the lens surface of the n-th lens is not particularly limited, but for example, by setting the image side of the n-th lens to a surface having a curvature, when light incident on the imaging lens is reflected at the image surface and enters the image side surface of the n-th lens, it is possible to prevent the re-reflected light from entering the image surface. That is, the occurrence of ghost can be suppressed by making the re-reflected light enter outside the image plane.

(4) Other lenses

When the imaging lens is a 5-piece lens (n is 5), the imaging lens is preferably configured by a 1 st lens, a 2 nd lens, an aperture stop, a lens Lp, a lens Gp, and an nth lens in this order from the object side. The order of arrangement of the lens Gp and the lens Lp may be reversed.

When n is 6. ltoreq. n.ltoreq.10, the lenses other than the 5 lenses, i.e., the 1 st lens, the 2 nd lens, the lens Lp, the lens Gp, and the n-th lens, are not particularly limited, but it is preferable that at least one glass lens having a substantial refractive power is disposed on each of the object side and the image side of the lens Lp and the lens Gp (or the lens Gp and the lens Lp) disposed adjacent to each other. By disposing at least 1 glass lens on the object side of the resin lens Lp (or the resin lens Gp), the influence of heat or ultraviolet rays on the resin lens from the object side can be suppressed. Further, by disposing at least 1 glass lens on the image side of the resin lens Gp (or the resin lens Lp), it is possible to suppress the influence of heat (for example, heat received from an image sensor or the like) or ultraviolet rays (for example, light reflected on the image plane) received from the image side.

(5) Lenses before and after the diaphragm

The stop here means an aperture stop that defines the beam diameter of the lens, that is, an aperture stop that defines Fno of the lens. In this imaging lens, the object side of the diaphragm is set as a 1 st group, and the image side of the diaphragm is set as a 2 nd group. The lens disposed closest to the image side in group 1 and the lens disposed closest to the object side in group 2 preferably have positive refractive power. By disposing the aperture stop between the positive lenses, the lens interval before and after the aperture stop can be minimized, and the total optical length can be shortened. Further, by disposing the aperture stop between the positive lenses, the effective diameters of the lenses before and after the aperture stop can be made small, and the aberration occurring between the 1 st group and the 2 nd group can be corrected well.

1-1-2. group composition

The lens configuration of the imaging lens is as described above, and the following describes the 1 st group, the 2 nd group, and the aperture stop in more detail.

(1) Group 1

a) Form a lens

The 1 st group preferably includes the 1 st lens and the 2 nd lens, and is substantially composed of 3 or less lenses. The 1 st group is composed of 3 or less lenses, so that the imaging lens can be easily reduced in size and weight.

b) Focal power

Group 1 preferably has a negative optical power as a whole. By arranging the negative power in the 1 st group, the optical configuration can be made negative first, so that it is easier to realize a wide angle of view and to reduce the front lens diameter compared to the angle of view.

c) Positive lens

In the case where group 1 has negative optical power, group 1 preferably contains at least 1 lens having positive optical power. By setting the group 1 having negative refractive power as a whole to a configuration including positive refractive power, curvature of field and chromatic aberration can be corrected well, and an imaging lens with high optical performance can be easily realized.

The lens arranged most to the image side in group 1 preferably has positive optical power. For example, in the case where the 1 st group is composed of 2 lenses, the 2 nd lens preferably has positive power. In addition, when the 1 st group is composed of 3 lenses, the 3 rd lens arranged 3 rd from the object side preferably has positive refractive power. By disposing a lens having positive refractive power adjacent to the most image side of the group 1, that is, to the object side of the aperture stop, distortion aberration and astigmatism generated in the group 1 lens can be corrected well, which is advantageous for achieving high resolution and wide angle at the peripheral image height.

In the case where the lens disposed closest to the image side in group 1 has positive refractive power, the abbe number at the d-line of the lens is preferably smaller than 65. Further, the abbe number of the lens at the d-line is preferably larger than 23, more preferably larger than 44. By disposing a lens having such dispersion characteristics on the most image side of the group 1, that is, on the object side of the stop, chromatic aberration of magnification can be corrected well.

Further, the image side of the lens disposed closest to the image side in group 1 is preferably a convex surface. Since the lens is disposed immediately before the stop, by setting the image side of the lens to be convex, it is possible to control both the ray angles of the axial rays and the optical axis and the ray angles of the peripheral rays and the optical axis, and reduce these ray angles after passing through the lens immediately after the stop. Therefore, the angles of the light rays incident on the resin lenses arranged in the group 2 are also reduced, and the variation in the angle of view due to the temperature change can be suppressed. In this case, by disposing the lens having positive refractive power on the most object side in the group 2 and disposing the lens Gp on the image side of the lens having positive refractive power, the light ray angles with respect to the lens Gp and the lens Lp can be further reduced, and variation in the angle of view due to temperature change can be suppressed.

d) Negative lens

In the case where group 1 has negative optical power, group 1 contains at least 1 lens having negative optical power. Therefore, the 1 st lens or the 2 nd lens preferably has a negative power. In particular, by disposing negative refractive power to the 1 st lens disposed closest to the object side in the imaging lens, as described above, it is easy to realize a wide angle of view, and the front lens diameter is reduced compared to the angle of view. In this case, by including 2 lenses having negative refractive power in the 1 st group, the negative refractive power arranged in the 1 st group can be dispersed to the 2 lenses, and spherical aberration and chromatic aberration occurring in the 1 st group can be more easily suppressed, thereby realizing an imaging lens having high optical performance.

It is preferable that the abbe number at the d-line of at least 1 lens having negative power included in the group 1 is larger than 38 in correcting chromatic aberration. In the case where the 1 st group includes 2 lenses having negative optical power, the abbe number at the d-line of these 2 lenses is preferably larger than 38, preferably larger than 44. In addition, in the case where the 1 st group includes 2 lenses having negative refractive power, the abbe number at the d-line of any one of the 1 lenses is more preferably greater than 50.

e) Aspherical lens

The lenses constituting the 1 st group are larger in diameter than the lenses constituting the 2 nd group. In the wide-angle lens, correction of curvature of field tends to be insufficient. Accordingly, if the lens disposed on the object side is also an aspheric lens in group 1, curvature of field can be more effectively corrected by setting the lens disposed on the image side as an aspheric lens in group 1.

(2) Group 2

a) Form a lens

The 2 nd group includes the above lens Gp and the n-th lens. The lenses Lp arranged adjacent to the lens Gp may be arranged in the 1 st group, but are preferably arranged in the 2 nd group together with the lens Gp. Further, it is preferable that at least 1 glass lens is provided on each of the object side and the image side of the lens Gp and the lens Lp disposed adjacent to each other, and as described above, the glass lens is also preferably disposed in the 2 nd group.

The object-side surface of the lens disposed closest to the object side in group 2 may be either convex or concave. In the case where the object-side most surface in group 2 is convex, the distortion aberration at a low image height can be made large, and the difference in angular resolution from the periphery can be kept small. On the other hand, in the case where the surface closest to the object side in group 2 is a concave surface, the distortion aberration at a low image height can be kept small, and the angular resolution at the center of the screen can be kept large.

b) Focal power

Group 2 preferably has a positive optical power as a whole. By arranging negative power for the 1 st group and positive power for the 2 nd group, astigmatism occurring in the 1 st group can be corrected well by the 2 nd group, a wider angle of view can be achieved and an imaging lens with high optical performance can be obtained.

c) Positive lens

In the case where group 2 has a positive power, group 2 preferably contains at least 2 lenses having a positive power. This makes it possible to arrange strong positive power for the 2 nd group, correct the astigmatism and the like well, and suppress the curvature of each lens surface from becoming excessively large. Further, by configuring to include at least 2 lenses having positive refractive power, curvature of field can be corrected well.

The lens disposed closest to the object side in group 2, i.e., the lens disposed immediately after the stop, preferably has positive optical power. If a lens having strong positive power is disposed on the most object side in group 2, negative distortion can be obtained, the angular resolution near the optical axis can be maintained high, and a wide angle of view can be achieved. In this case, by setting the lens disposed closest to the image side in the 1 st group to a lens having a convex surface on the image side, the change in the angle of view can be suppressed satisfactorily even when the ambient temperature changes, as described above, and the change in the focal position can also be suppressed satisfactorily.

Further, in the lens disposed closest to the object side in the group 2, the difference between the incident angle of the off-axis ray and the incident angle of the axial ray is small. Therefore, in the lens disposed most toward the object side in group 2, axial chromatic aberration can be corrected more effectively than off-axis chromatic aberration. Therefore, the lens having positive power included in group 2 is preferably low in dispersion, and the abbe number at the d-line is preferably larger than 53, more preferably larger than 63 in terms of well correcting chromatic aberration.

Further, as described above, when the n-th lens disposed most to the image side in the 2 nd group is 6. ltoreq.n, the n-th lens has positive power. In addition, the lens Lp also preferably has positive power.

d) Negative lens

In the case where group 2 has a positive power, group 2 preferably contains at least 1 lens having a negative power. By arranging at least 1 lens having negative power in the 2 nd group having positive power, chromatic aberration can be corrected well.

In addition, it is preferable to arrange the entrance pupil position on the object side as much as possible in order to achieve miniaturization of the imaging lens in the radial direction. In group 2, by disposing at least 1 lens having negative refractive power on the object side of the lens having positive refractive power, the entrance pupil position can be easily disposed on the object side, and downsizing in the radial direction can be achieved.

Further, in group 2, if a lens having negative refractive power is disposed on the image side of a lens having positive refractive power, chromatic aberration in the axial direction and in the vicinity of the axial direction can be corrected well.

In group 2, the lens having negative optical power preferably has a refractive index at the d-line larger than 1.60, more preferably larger than 1.65. A large refractive index of a lens having negative power is more preferable in realizing miniaturization of the imaging lens.

e) Resin lens

Group 2 includes a lens Gp and a lens Lp. Of the n lenses constituting the imaging lens, all of the resin lenses are preferably arranged in the 2 nd group. By disposing all the resin lenses on the image side of the aperture, the change in the field angle due to the change in the ambient temperature can be suppressed more favorably, and the change in the focal position can be suppressed more favorably, as compared with the case where the resin lenses are disposed on the object side of the aperture.

The imaging lens may include a resin lens in addition to the lens Gp and the lens Lp, but the resin lens among the n lenses constituting the imaging lens is more preferably 2 lenses, that is, the lens Gp and the lens Lp. If only these 2 lenses are resin lenses, the number of optical elements that have a large influence on the change in the field angle and the change in the focal position when the ambient temperature changes does not increase excessively, and it is easy to control these changes. Further, for example, it is easier to suppress the variation of the angle of field and the variation of the focal position not only at a temperature greatly different from the room temperature, such as 125 ℃ or-20 ℃, but also in a temperature range between the room temperature and ± 20 ℃. Further, by using the 2 lenses made of resin, it is possible to easily cancel out the angular variation of field, the variation of focal position, various aberrations, and the like, which are generated in both lenses, linearly by appropriately adjusting the refractive power, surface shape, and the like, which are disposed in each lens. Further, the resin lens is yellowed by the influence of ultraviolet rays and heat, and the transmittance of light having a wavelength of blue, which is a complementary color, is lowered. Yellowing occurs due to the influence of heat, ultraviolet rays, aging, and the like, which are applied to the molding. With respect to the influence of such aging, by setting the resin lenses to 2, chromatic aberration can be corrected more favorably than in the case of setting the resin lenses to 1.

1-2. conditional formula

The imaging lens preferably has the above-described configuration, and satisfies at least 1 or more of the following conditional expressions.

1-2-1. conditional expression (1)

-0.59＜f/fp＜-0.01·····(1)

Wherein the content of the first and second substances,

f: the focal length of the imaging lens

fp: combined focal length of lens Gp and lens Lp

The conditional expression (1) is an expression that specifies the ratio of the focal length of the imaging lens to the combined focal length of the lens Gp and the lens Lp. By satisfying the conditional expression (1), the combined refractive power of the resin lens is within an appropriate range, and the change in the field angle and the change in the focal position due to the lens Lp can be used to cancel out the change in the field angle and the change in the focal position due to the lens Gp, thereby reducing the change in the field angle and the change in the focal position of the imaging lens due to the change in the ambient temperature. When conditional expression (1) is satisfied, the combined power of the lens Gp and the lens Lp has a negative value. If the ambient temperature changes, the field angle and the focal position may change due to not only the resin lens but also the glass lens. At this time, since the change in the field angle and the change in the focal position due to the glass lens have opposite signs to the change in the field angle and the change in the focal position due to the resin lens when the conditional expression (1) is satisfied, the change in the field angle, the change in the focal position, and the change in the back focus of the imaging lens due to the change in the ambient temperature can be suppressed by offsetting these changes. Further, as described above, the lens Gp is preferably a biconcave lens, and the lens Lp is preferably a biconvex lens. In this case, since the synthetic optical power in the range specified by the above conditional expression (1) can be obtained while preventing the curvature of the lens surface from becoming excessively large, the change in the field angle, the change in the focal position, and the change in the back focus due to the change in the ambient temperature can be further reduced.

On the other hand, if the numerical value of conditional expression (1) is equal to or greater than the upper limit, when the atmospheric temperature changes, the change in the field angle, the change in the focal position, and the change in the back focus due to the glass lens can be suppressed. On the other hand, if the numerical value of the conditional expression (1) is equal to or less than the lower limit value, the combined refractive power of the lens Gp and the lens Lp is too strong, and when the ambient temperature changes, the change in the field angle and the change in the focal position of the resin lens become large, and it is difficult to sufficiently suppress the change in the field angle and the change in the focal position of the imaging lens due to the change in the ambient temperature, which is not preferable.

In order to obtain the above-mentioned effects, the lower limit of the conditional formula (1) is more preferably-0.55, still more preferably-0.4, still more preferably-0.3, and still more preferably-0.25. Further, the upper limit of the conditional formula (1) is more preferably-0.03, still more preferably-0.05, and still more preferably-0.07. When these preferable lower limit values or upper limit values are used, the inequality numbers (≦) with the equal sign may be replaced with the inequality numbers (<) in the conditional expression (1). The same applies to other conditional expressions as a principle.

1-2-2. conditional expression (2)

0.1＜ctGA/f＜1.2·····(2)

Wherein the content of the first and second substances,

ctGA: the sum of the central thickness of the lens Gp and the central thickness of the lens Lp

The conditional expression (2) is an expression for specifying a ratio of a sum of a center thickness of the lens Gp and a center thickness of the lens Lp to a focal length of the imaging lens. By satisfying the conditional expression (2), the sum of the center thicknesses of the lens Gp and the lens Lp is not excessively large, and when these lenses yellow due to the influence of ultraviolet rays, heat, or the like, a decrease in transmittance of blue light rays as a complementary color thereof can be suppressed.

In this case, it is preferable that the conditional expression (2) is satisfied and the center thickness of the lens Gp is smaller than the center thickness of the lens Lp. As described above, the lens Gp is a resin material having a refractive index N and an abbe number V satisfying predetermined conditions. The material of the lens Gp is more susceptible to yellowing, and when yellowing occurs, the center thickness of the lens Gp is thinner, so that the influence on the transmittance and the spectral characteristics can be reduced, and good image resolution performance can be maintained for a long period of time.

On the other hand, if the numerical value of the conditional expression (2) is equal to or greater than the upper limit value, the sum of the center thicknesses of the lens Gp and the lens Lp becomes excessively large, and the light transmittance of blue light decreases when these lenses yellow, so that it is difficult to correct chromatic aberration. On the other hand, if the numerical value of conditional expression (2) is less than or equal to the lower limit, the sum of the central thicknesses of the lens Gp and the lens Lp is too small, making it difficult to mold both lenses with high precision and to obtain a desired surface shape.

In order to obtain the above-described effects, the lower limit of conditional expression (2) is preferably 0.30, more preferably 0.50, and still more preferably 0.55. The upper limit of conditional expression (2) is preferably 1.00, more preferably 0.90.

1-2-3. conditional expression (3)

0.9＜fs/f＜4.5·····(3)

Wherein the content of the first and second substances,

fs: focal length of lens arranged adjacent to image side of diaphragm

The conditional expression (3) is an expression for specifying a ratio of a focal length of a lens disposed adjacent to the image side of the aperture stop to a focal length of the imaging lens. When the conditional expression (3) is satisfied, the lens disposed adjacent to the image side of the stop has positive refractive power of an appropriate magnitude, and the incident angle of the light beam with respect to the lens Gp disposed adjacent to the image side of the stop can be reduced. Therefore, when the ambient temperature changes, the variation in the incident angle of the light beam with respect to the lens Gp is small, and the variation in the angle of field can be suppressed. Further, since the negative distortion can be increased by satisfying the conditional expression (3), a wide angle of view can be realized while maintaining high angular resolution in the vicinity of the optical axis.

On the other hand, if the numerical value of conditional expression (3) is equal to or greater than the upper limit value, the optical power of the lenses disposed adjacent to the image side of the stop becomes too strong, the negative distortion becomes larger than an appropriate range, and the imaging performance at the periphery is degraded. On the other hand, if the numerical value of conditional expression (3) is equal to or less than the lower limit, the refractive power of the lens disposed adjacent to the image side of the stop is too small, and the effect of reducing the incident angle of the light beam to the lens Gp cannot be obtained, and the effect of suppressing the change in the field angle associated with the change in the ambient temperature becomes small.

In terms of obtaining the above-described effects, the lower limit value of conditional formula (3) is preferably 1.50, more preferably 1.80. The upper limit of conditional expression (3) is preferably 4.20, more preferably 4.00, still more preferably 3.80, and yet more preferably 3.60.

1-2-4. conditional expression (4)

1.8＜f×tan(θ)/Yh＜3.2·····(4)

Wherein the content of the first and second substances,

yh: the maximum image height of the imaging lens

θ: the half field angle of the imaging lens

The conditional expression (4) is an expression for specifying a ratio of an ideal image height (f × tan (θ)) to a maximum image height of the imaging lens. Satisfying the conditional expression (4) can increase the negative distortion, maintain high angular resolution near the optical axis, and realize a wide angle of view. In other words, the focal length of the imaging lens can be made longer than the maximum image height.

On the other hand, if the numerical value of conditional expression (4) is equal to or greater than the upper limit, the negative distortion is too large, and it is difficult to maintain the imaging performance in the periphery. On the other hand, if the numerical value of conditional expression (4) is equal to or less than the lower limit value, it is difficult to maintain the angular resolution near the optical axis high, and it is difficult to obtain a long focal length from the maximum image height.

In terms of obtaining the above-described effects, the lower limit value of conditional expression (4) is preferably 2.00, more preferably 2.10. The upper limit of conditional expression (4) is preferably 3.00, more preferably 2.90, and still more preferably 2.80.

1-2-4. conditional expression (5)

1.8＜Ng1＜2.0·····(5)

Wherein the content of the first and second substances,

ng 1: refractive index of 1 st lens corresponding to d-line

The conditional expression (5) is an expression for defining the refractive index of the 1 st lens corresponding to the d-line. By satisfying the conditional expression (5), it is advantageous in that petzval sum is easily corrected and a wide angle of view is realized by disposing the 1 st lens made of a high refractive index glass material on the most object side of the imaging lens.

In order to obtain the above-described effects, the lower limit of conditional expression (5) is preferably 1.82, and more preferably 1.84. The upper limit of conditional expression (5) is preferably 1.95, more preferably 1.90, and still more preferably 1.88.

1-2-6. conditional expression (6)

1.55＜Ng2＜1.89·····(6)

Wherein the content of the first and second substances,

ng 2: refractive index of 2 nd lens corresponding to d-line

Conditional expression (6) is an expression for defining the refractive index of the 2 nd lens corresponding to the d-line. By satisfying conditional expression (6), the 2 nd lens disposed second from the object side in the imaging lens is made of low refractive index glass, and it is easy to correct the petzval sum.

In order to obtain the above-described effects, the lower limit of conditional expression (6) is preferably 1.58, more preferably 1.60. The upper limit of conditional expression (6) is preferably 1.85, more preferably 1.80, and still more preferably 1.79.

Further, Ng1 > Ng2 is preferable, that is, the 1 st lens is made of glass having a higher refractive index than the 2 nd lens. In this case, by disposing the negative refractive power in the 1 st lens, the amount of the high refractive index glass material, which is more expensive than the low refractive index glass material, can be reduced, and the image plane property can be improved while reducing the cost of the imaging lens.

1-2-7. conditional expression (7)

0.01＜Dpp/f＜0.40·····(7)

Wherein the content of the first and second substances,

dpp: the distance between the lens Gp and the lens Lp on the optical axis

The conditional expression (7) is an expression for specifying a ratio between an interval between the lens Gp and the lens Lp on the optical axis and a focal length of the imaging lens. In addition, the value of Dpp is always set to a positive value regardless of the order of arrangement of the lenses Gp and Lp. By satisfying the conditional expression (7), the incident height of the principal ray to each image height in the lens Gp and the lens Lp adjacent to each other is reduced, and the decentering sensitivity of the lens surfaces of both lenses is similar even if the decentering sensitivity is different in magnitude, because the lenses are made of resin, and the balance thereof is similar, so that the variation in the angle of view in both lenses caused by the change in the ambient temperature is easily cancelled out linearly, and the variation in the angle of view of the imaging lens can be suppressed. Further, by satisfying the conditional expression (7), the distance between the lens Gp and the lens Lp can be appropriately maintained, and the manufacturing error at the time of assembling the lens can be made within the tolerance range, and a lens having excellent optical performance can be manufactured with high yield.

On the other hand, if the numerical value of conditional expression (7) is equal to or greater than the upper limit value, the interval between the lens Gp and the lens Lp on the optical axis increases, the incident height of the principal ray to each image height increases, the incident position of the principal ray with a change in the ambient temperature easily fluctuates, and it is difficult to sufficiently suppress the fluctuation in the angle of view of the imaging lens. On the other hand, if the numerical value of conditional expression (7) is equal to or less than the lower limit, the distance between the lenses Gp and Lp on the optical axis is too small, and there is a possibility that lens surfaces may collide with each other due to manufacturing tolerances of the respective lenses, and it is difficult to manufacture the imaging lens with high yield.

In order to obtain the above-described effects, the lower limit of conditional formula (7) is preferably 0.015, more preferably 0.020, and still more preferably 0.025. The upper limit of conditional expression (7) is preferably 0.18, more preferably 0.16, still more preferably 0.13, and yet more preferably 0.11.

1-2-8. conditional expression (8)

-0.3＜Pair×f＜0.3·····(8)

Wherein the content of the first and second substances,

pair: the sum of the power of the object-side surface and the power of the image-side surface of the air lens formed between the lens Gp and the lens Lp is a value expressed by (1-n1)/r1- (1-n2)/r2

In this case, the amount of the solvent to be used,

n 1: refractive index of lens arranged on object side among lens Gp and lens Lp corresponding to d-line

n 2: refractive index corresponding to d-line of lens arranged on image side among lens Gp and lens Lp

r 1: radius of curvature of object side surface of the air lens

r 2: radius of curvature of image side surface of the air lens

The conditional expression (8) is an expression for specifying the refractive power of the air lens between the lens Gp and the lens Lp. If the conditional expression (8) is satisfied, the refractive power of the air lens decreases, the incident height of the principal ray to each image height in the mutually adjacent lens Gp and lens Lp becomes lower, the principal rays have similar values, and the surface shape actions of both lenses are set to the same degree. Therefore, the variations in the angle of view of the two lenses caused by the changes in the ambient temperature can be easily cancelled out, and the variations in the angle of view of the imaging lens can be suppressed.

In order to obtain the above-mentioned effects, the lower limit of conditional formula (8) is preferably-0.25, more preferably-0.20, and still more preferably-0.15. The upper limit of conditional expression (8) is preferably 0.25, more preferably 0.20, still more preferably 0.15, and yet more preferably 0.10.

1-2-9. conditional expression (9)

-9.0＜f1G/f＜0.0·····(9)

Wherein the content of the first and second substances,

f 1G: focal length of group 1

Conditional expression (9) is an expression that specifies the ratio of the focal length of the 1 st group to the focal length of the imaging lens. When conditional expression (9) is satisfied, group 1 has negative power. By arranging negative power for group 1, large negative distortion is likely to occur, and a wide angle of view can be achieved while maintaining high angular resolution near the optical axis.

On the other hand, if the numerical value of conditional expression (9) is equal to or greater than the upper limit, large negative distortion is less likely to occur, and it is difficult to achieve a wide angle of view. On the other hand, if the numerical value of conditional expression (9) is equal to or less than the lower limit, the negative distortion becomes large beyond an appropriate range, and it is difficult to obtain an imaging lens with high optical performance.

In terms of obtaining the above-mentioned effects, the lower limit value of conditional formula (9) is preferably-8.50, more preferably-8.00, further preferably-7.50, still further preferably-7.00, still further preferably-6.00, still further preferably-5.00, most preferably-4.50. Further, the upper limit of the conditional formula (9) is preferably-0.50, more preferably-1.00, still more preferably-1.50, and still more preferably-2.00.

1-2-10. conditional expression (10)

0.40＜DD/LL＜0.95·····(10)

Wherein the content of the first and second substances,

DD: sum of center thicknesses of lenses from 1 st lens to n-th lens

LL: distance on optical axis from object side surface of 1 st lens to image side surface of n-th lens

The conditional expression (10) is a ratio of a total of center thicknesses of n lenses constituting the imaging lens to a distance on an optical axis from an object side surface of the 1 st lens to an image side surface of the n-th lens. The n lenses are held by a lens frame (lens barrel) or the like. If the atmospheric temperature greatly changes, the thickness of the lens and the like may change. In order to suppress the change in the angle of field due to the change in the ambient temperature, it is necessary to keep each lens from being tilted by the frame regardless of the ambient temperature. In order to suppress the inclination of the lenses, there are a method of increasing the thickness of each lens and a method of strongly pressing the imaging lens from the object side surface and the image side surface. By satisfying the conditional expression (10), the center thickness of each lens and the pressing force from both sides of the imaging lens can be set to appropriate ranges, and each lens can be held by the lens frame so as not to tilt even if the ambient temperature changes.

In order to obtain the above-described effects, the lower limit of conditional expression (10) is preferably 0.45, more preferably 0.50, and still more preferably 0.52. The upper limit of conditional expression (10) is preferably 0.90, more preferably 0.85, still more preferably 0.82, yet more preferably 0.75, yet more preferably 0.70, yet more preferably 0.68, and most preferably 0.60.

1-2-11. conditional expression (11)

6.0＜L/Yh＜10.0·····(11)

Wherein the content of the first and second substances,

l: the total optical length of the imaging lens (distance on the optical axis from the object side lens surface of the 1 st lens to the image surface)

Yh: the maximum image height of the imaging lens

The conditional expression (11) is an expression for specifying a ratio of the optical total length to the maximum image height of the imaging lens. By satisfying the conditional expression (11), it is possible to arrange an appropriate power for the 1 st group, generate negative distortion, maintain high angular resolution in the vicinity of the optical axis, and realize a wide angle of view.

On the other hand, if the numerical value of conditional expression (11) is equal to or less than the lower limit, the optical focus of group 1 is too weak, so that negative distortion is less likely to occur, and it is difficult to obtain an imaging lens having a wide angle of view compared to the focal length. On the other hand, if the numerical value of conditional expression (11) is the upper limit value or more, the optical focus of group 1 is too strong, and the imaging performance at the periphery is degraded. Further, the lenses constituting group 1 have large diameters, which is not preferable in terms of downsizing, weight saving, and cost reduction of the imaging lens.

In order to obtain the above-described effects, the lower limit of conditional expression (11) is preferably 6.50, and more preferably 7.00. The upper limit of conditional expression (11) is preferably 9.00, more preferably 8.50, still more preferably 8.20, and yet more preferably 8.05.

1-2-12 conditional expression (12)

-5.0＜fL/f＜4.0·····(12)

Wherein the content of the first and second substances,

fL: focal length of nth lens

The conditional expression (12) is an expression for specifying a ratio of a focal length of an n-th lens disposed closest to the image side in the imaging lens to a focal length of the imaging lens. Satisfying the conditional expression (12) suppresses an increase in the incident angle of light to the image plane, and appropriately maintains the amount of peripheral light.

On the other hand, if the numerical value of conditional expression (12) is not less than the upper limit, the back focus is too long and the optical total length becomes long, which is not preferable. On the other hand, if the numerical value of conditional expression (12) is less than or equal to the lower limit, the light incident angle on the image plane becomes large, so-called vignetting occurs, and the peripheral light amount decreases, which is not preferable.

In terms of obtaining the above-mentioned effects, the lower limit value of conditional formula (12) is preferably-4.70, more preferably-4.40, further preferably-4.20, still further preferably-3.00, still further preferably-2.00, still further preferably 0.00. The upper limit of conditional expression (12) is preferably 3.50, more preferably 3.00, still more preferably 2.85, and yet more preferably 2.75.

According to the imaging lens described above, the resin lens is included, so that the reduction in weight and the reduction in cost are achieved, and the change in the field angle and the change in the focal position due to the change in the ambient temperature can be suppressed. In addition, negative distortion is generated, the angular resolution in the vicinity of the optical axis is maintained high, and an imaging lens having a wide angle of view compared to the focal length can be obtained.

2. Image pickup apparatus

Next, an imaging device according to the present invention will be described. An imaging device according to the present invention includes the imaging lens according to the present invention and an imaging element that is provided on an image plane side of the imaging lens and converts an optical image formed by the imaging lens into an electric signal.

Here, the imaging element and the like are not particularly limited, and a solid-state imaging element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor may be used. The imaging device according to the present invention is suitable as an imaging device using a solid-state imaging element. It is obvious that the imaging device may be a fixed-lens type imaging device in which the lens is fixed to the housing, or an interchangeable-lens type imaging device such as a single-lens reflex camera or a mirrorless single-lens camera.

The imaging device of the present invention more preferably includes: an image processing unit that performs electric processing on captured image data acquired by the image pickup device to change the shape of a captured image, an image correction data holding unit that holds image correction data, an image correction program, and the like for processing the captured image data in the image processing unit, and the like. When the lens is downsized, distortion aberration or chromatic aberration of magnification is likely to occur. In this case, it is preferable that the image correction data holding unit holds data for correcting distortion aberration or chromatic aberration of magnification in advance, and the image processing unit corrects distortion aberration or chromatic aberration of magnification using the data. According to such an imaging device, the lens can be further downsized, and a beautiful captured image can be obtained and the imaging device can be downsized.

In the imaging lens, since the angular resolution near the optical axis is high and a wide angle of view can be achieved compared to the focal length, by applying the imaging device to a vehicle-mounted lens, a lens for an unmanned aerial vehicle, and the like, particularly a sensor camera, it is possible to detect a distant object with high accuracy in front of a moving object such as a vehicle or an unmanned aerial vehicle in the direction of travel, and recognize an object (an obstacle, a traffic light, a road traffic sign, and the like) around the moving object in a wide range.

Next, examples are shown and the present invention is specifically explained. However, the present invention is not limited to the following examples.

[ example 1]

(1) Optical construction

Fig. 1 is a lens cross-sectional view of an imaging lens in infinity focusing of an imaging lens according to embodiment 1 of the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having positive refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having negative refractive power, and a 6 th lens L6 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 2 nd lens L2.

In the imaging lens, the 1 st group is constituted by the 1 st lens L1 and the 2 nd lens L2, and the 2 nd group is constituted by the 3 rd lens L3 to the 6 th lens L6. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a positive meniscus lens with a concave surface facing the object side, the 3 rd lens L3 is a biconvex lens, the 4 th lens L4 is a biconvex lens, the 5 th lens L5 is a biconcave lens, and the 6 th lens L6 is a biconvex lens. The 5 th lens L5 is a lens Gp of the present invention, and the 4 th lens L4 is a lens Lp of the present invention. In addition, the nth lens is the 6 th lens L6. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

The "IMG" shown in fig. 1 is an image plane, and specifically represents an imaging plane of a solid-state imaging device such as a CCD sensor or a CMOS sensor, or a thin film surface of a silver halide thin film. Further, a parallel flat plate having no substantial optical power, such as the cover glass CG, is provided on the object side of the image forming surface IMG. These points are the same in the cross-sectional views of the lenses shown in the other embodiments, and therefore the description thereof is omitted below.

(2) Numerical example

Next, a numerical example to which specific numerical values are applied of the lens will be described. The following description refers to "lens data", "various specification values", "variable intervals", "aspherical coefficients", and "focal lengths of the respective lenses". The values of the conditional expressions (table 1) and the values used in the conditional expressions (table 2) are collectively shown in example 8. The viewing angle variation range of this embodiment is also shown in a summary manner after embodiment 8.

In the lens data, "surface number" represents the number of lens surfaces counted from the object side, "r" represents the radius of curvature of the lens surfaces, "d" represents the interval of the lens surfaces on the optical axis, "Nd" represents the refractive index corresponding to d-line (wavelength λ is 587.6nm), and "vd" represents the abbe number corresponding to d-line. In addition, "h" shown in the column following the "surface number" indicates that the lens surface is an aspherical surface, and "S" indicates an aperture stop. In each table, all units of length are "mm", and all units of angle of view are "°". In addition, "INF" of the curvature radius means a plane.

In various specification values, "F" represents the focal length of the lens, "Fno" represents the F value, and "θ" represents the half field angle.

The aspherical surface coefficient is a value when an aspherical surface shape is defined by the following equation.

(Y)＝CY²/[1+{1-(1+k)·C²Y²}^1/2]+A4·Y⁴+A6·Y⁶+A8·Y⁸+A10·Y¹⁰+A12·Y¹²+A14·Y¹⁴

Wherein "E. + -. XX" represents an index notation, representing ". times.10^±XX". In the above equation, "C" represents a curvature at the vertex of the surface, "Y" represents a height from the optical axis in a direction perpendicular to the optical axis, "k" represents a conical coefficient, and "An" represents An n-order aspheric coefficient.

The focal length of each lens means the focal length of each of the 1 st lens to the nth lens (the 6 th lens in the present embodiment) constituting the imaging lens.

The matters in the tables are the same in the tables shown in the other embodiments, and therefore, the description thereof will be omitted below.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	29.432	1.300	1.85135	40.10
2*	4.370	2.502
					3	-9.778	5.300	1.74400	44.90
4	-9.322	0.200
					5S	0.000	1.748
6*	11.422	6.300	1.49700	81.61
					7*	-8.167	3.000
8*	10.066	2.354	1.54472	55.86
					9*	-10.163	0.200
10*	-15.768	0.933	1.63980	23.27
					11*	5.024	1.680
12	8.000	3.536	1.49700	81.61
					13	-17.589	0.400
14	0.000	0.400	1.51680	64.20
					15	0.000	0.700
16	0.000	0.500	1.51680	64.20
					17	0.000	1.440

(various specification values)

f	5.001
		Fno	1.640
θ	66.000

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	0.0000	-1.12816E-03	9.98937E-06	4.20131E-06	-3.15432E-07
2	0.0000	-8.93175E-04	7.02556E-05	-2.09785E-05	6.23697E-06
						6	0.0000	1.71692E-04	-4.08681E-05	1.00706E-05	-1.02271E-06
7	0.0000	5.96952E-04	-9.68873E-07	2.33138E-06	-2.02622E-07
						8	0.0000	1.36975E-04	3.18314E-05	-6.58818E-06	6.77951E-07
9	0.0000	4.70226E-03	-7.71973E-04	7.80790E-05	-4.61142E-06
						10	0.0000	-6.95366E-04	-1.90014E-04	3.99984E-05	-3.09054E-06
11	0.0000	-6.47889E-03	6.44737E-04	-5.24931E-05	2.89671E-06

(focal length of each lens)

	Focal length
		1 st lens	-6.175
2 nd lens	45.090
		No. 3 lens	10.727
No. 4 lens	9.681
		No. 5 lens	-5.853
No. 6 lens	11.596

Fig. 2 shows a longitudinal aberration diagram of the imaging lens in focusing on an object at infinity. The longitudinal aberration diagrams shown in the respective diagrams are spherical aberration (mm), astigmatism (mm), and distortion aberration (%) in this order from the left side of the diagram. In the graph showing the spherical aberration, the ordinate represents a ratio to the open F value, the abscissa represents defocus, the solid line represents the spherical aberration on the d-line (wavelength λ 587.6nm), the broken line represents the spherical aberration on the g-line (wavelength λ 435.8nm), and the dotted line represents the spherical aberration on the C-line (wavelength λ 656.3 nm). In the graph showing astigmatism, the vertical axis represents a half field angle (θ), the horizontal axis represents defocus, the solid line represents a sagittal image plane (X) corresponding to the d-line, and the dashed dotted line represents a meridional image plane (Y) corresponding to the d-line. In the graph showing distortion aberration, the ordinate represents a half field angle (θ), and the abscissa represents distortion aberration. The items related to these longitudinal aberration diagrams are also the same in the longitudinal aberration diagrams shown in other embodiments, and therefore the description thereof is omitted below.

[ example 2]

(1) Optical construction

Fig. 3 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 2 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having positive refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having negative refractive power, and a 6 th lens L6 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 2 nd lens L2. An infrared cut filter IRCF is disposed on the image side of the 6 th lens L6.

In the imaging lens, the 1 st group is constituted by the 1 st lens L1 and the 2 nd lens L2, and the 2 nd group is constituted by the 3 rd lens L3 to the 6 th lens L6. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a positive meniscus lens with a concave surface facing the object side, the 3 rd lens L3 is a positive meniscus lens with a concave surface facing the object side, the 4 th lens L4 is a biconvex lens, the 5 th lens L5 is a biconcave lens, and the 6 th lens L6 is a biconvex lens. The 5 th lens L5 is a lens Gp of the present invention, and the 4 th lens L4 is a lens Lp of the present invention. In addition, the nth lens is the 6 th lens L6. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 4 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	15.549	1.020	1.85945	40.10
2*	3.594	1.892
					3	-15.880	5.050	1.76356	25.05
4	-9.810	3.179
					5S	0.000	0.831
6*	-57.457	3.000	1.62250	63.85
					7*	-6.671	0.502
8*	9.347	2.839	1.54845	55.86
					9*	-11.673	0.131
10*	-21.794	0.658	1.65011	23.27
					11*	5.548	1.645
12	8.490	3.900	1.49932	81.61
					13	-16.380	0.209
14	0.000	0.400	1.51986	64.20
					15	0.000	3.800
16	0.000	0.500	1.51986	64.20
					17	0.000	0.441

(various specification values)

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	-11.0932	-1.05307E-03	2.48092E-05	-6.32106E-07	8.01807E-09
2	-2.2391	4.26856E-03	-1.43811E-04	1.30452E-05	-5.76414E-07
						6	-102.2600	-4.11114E-04	1.96035E-05	-2.40571E-06	6.69177E-08
7	-0.2438	5.87629E-04	-2.27379E-05	1.64779E-07	-6.71160E-11
						8	1.4835	3.74202E-05	-1.99871E-05	1.32144E-09	4.30964E-10
9	-2.2258	3.88642E-04	-2.24705E-05	1.11713E-06	-4.20762E-09
						10	-9.9349	-3.67684E-04	-2.33039E-06	1.07500E-06	1.76362E-08
11	-0.6823	-8.77222E-04	4.11728E-05	-9.43928E-07	1.98950E-08

Noodle numbering	A12	A14
			1	0.00000E+00	0.00000E+00
2	-3.74014E-09	0.00000E+00
			6	0.00000E+00	0.00000E+00
7	1.35263E-10	0.00000E+00
			8	1.01483E-10	0.00000E+00
9	-6.13491E-10	0.00000E+00
			10	-1.92065E-09	0.00000E+00
11	-2.32902E-10	0.00000E+00

(focal length of each lens)

	Focal length
		1 st lens	-5.661
2 nd lens	24.711
		No. 3 lens	11.855
No. 4 lens	9.940
		No. 5 lens	-6.739
No. 6 lens	11.816

[ example 3]

(1) Optical construction

Fig. 5 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 3 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having positive refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having negative refractive power, and a 6 th lens L6 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 2 nd lens L2. An infrared cut filter IRCF is disposed on the image side of the 6 th lens L6.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 6 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	7.000	1.020	1.85639	40.12
2*	3.683	3.327
					3	-9.868	5.449	1.77621	49.62
4	-9.824	3.342
					5S	0.000	2.212
6*	-117.597	3.000	1.69661	53.25
					7*	-8.662	1.643
8*	10.094	3.254	1.54705	55.86
					9*	-6.206	0.299
10*	-6.245	0.658	1.64568	23.35
					11*	7.883	1.367
12	7.819	3.351	1.57125	56.04
					13	-67.092	0.200
14	0.000	0.400	1.51872	64.20
					15	0.000	3.1
16	0.000	0.500	1.51872	64.20
					17	0.000	0.089

(various specification values)

F	5.025
		Fno	1.460
θ	66.000

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	-4.5296	-9.10781E-04	3.20145E-05	-9.21571E-07	9.12712E-09
2	-1.9261	8.28543E-04	4.82284E-05	-4.18710E-09	5.17465E-08
						6	-102.2600	-4.19057E-04	1.99547E-05	-2.29612E-06	6.36185E-08
7	-1.4441	2.65982E-04	-1.89620E-05	-4.96467E-07	2.20374E-08
						8	2.2186	1.00108E-03	-3.88747E-05	-2.57950E-07	-1.23877E-08
9	-5.4721	1.00136E-03	-3.57265E-05	-7.72490E-07	5.90984E-08
						10	-4.2779	1.33602E-03	-2.59833E-05	-7.49990E-07	8.15476E-08
11	-5.0263	1.68290E-03	4.02696E-05	-2.43582E-06	5.78824E-08

Noodle numbering	A12	A14
			1	0.00000E+00	0.00000E+00
2	-3.70315E-09	0.00000E+00
			6	0.00000E+00	0.00000E+00
7	2.66965E-11	0.00000E+00
			8	5.48348E-10	0.00000E+00
9	-2.04384E-10	0.00000E+00
			10	-1.20385E-09	0.00000E+00
11	-7.57416E-10	0.00000E+00

(focal length of each lens)

	Focal length
		1 st lens	-10.574
2 nd lens	51.497
		No. 3 lens	13.273
No. 4 lens	7.558
		No. 5 lens	-5.300
No. 6 lens	12.462

[ example 4]

(1) Optical construction

Fig. 7 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 4 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having positive refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, and a 5 th lens L5 having negative refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 2 nd lens L2. An infrared cut filter IRCF is disposed on the image side of the 5 th lens L5.

In the imaging lens, the 1 st lens L1 and the 2 nd lens L2 form the 1 st group, and the 3 rd lens L3 to the 5 th lens L5 form the 2 nd group. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a positive meniscus lens with a concave surface facing the object side, the 3 rd lens L3 is a biconvex lens, the 4 th lens L4 is a biconvex lens, and the 5 th lens L5 is a biconcave lens. The 5 th lens L5 is a lens Gp of the present invention, and the 4 th lens L4 is a lens Lp of the present invention. The nth lens is a 5 th lens L5. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 8 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	52.286	1.300	1.85135	40.10
2*	8.029	2.676
					3	-9.355	6.779	1.62041	60.32
4	-8.644	2.200
					5S	0.000	2.655
6*	13.756	7.052	1.48749	70.40
					7*	-6.672	0.200
8*	9.784	2.228	1.54472	55.86
					9*	-8.429	0.528
10*	-7.366	2.000	1.63980	23.27
					11*	8.494	2.016
12	0.000	0.400	1.51680	64.20
					13	0.000	0.700
14	0.000	0.500	1.51680	64.20
					15	0.000	1.066

(various specification values)

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	0.0000	-4.47455E-06	4.05535E-06	3.55473E-06	-3.00732E-07
2	0.0000	-1.13217E-04	1.87200E-04	-2.44616E-05	6.16778E-06
						6	0.0000	-3.42830E-04	-3.72768E-05	8.06207E-06	-9.65974E-07
7	0.0000	9.91959E-04	-1.43563E-05	1.70205E-06	-1.59077E-07
						8	0.0000	4.88483E-04	8.87036E-07	-1.09623E-05	7.51874E-07
9	0.0000	2.96132E-03	-7.47074E-04	7.92548E-05	-4.68512E-06
						10	0.0000	2.72075E-04	-1.85051E-04	4.14583E-05	-3.02657E-06
11	0.0000	-4.62969E-03	6.44069E-04	-5.52801E-05	3.28406E-06

Noodle numbering	A12	A14
			1	9.37086E-09	-1.01629E-10
2	-6.18819E-07	2.17766E-08
			6	5.28288E-08	-1.08234E-09
7	1.03609E-08	-1.99251E-10
			8	-3.48786E-08	6.64742E-10
9	1.41934E-07	-1.66528E-09
			10	1.13727E-07	-1.56079E-09
11	-9.57011E-08	1.33647E-09

(focal length of each lens)

	Focal length
		1 st lens	-11.294
2 nd lens	39.426
		No. 3 lens	10.392
No. 4 lens	8.687
		No. 5 lens	-5.877

[ example 5]

(1) Optical construction

Fig. 9 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 5 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having positive refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having positive refractive power, a 6 th lens L6 having negative refractive power, and a 7 th lens L7 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 2 nd lens L2. An infrared cut filter IRCF is disposed on the image side of the 7 th lens L7.

In the imaging lens, the 1 st lens L1 and the 2 nd lens L2 form the 1 st group, and the 3 rd lens L3 to the 7 th lens L7 form the 2 nd group. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a positive meniscus lens with a concave surface facing the object side, the 3 rd lens L3 is a biconvex lens, the 4 th lens L4 is a positive meniscus lens with a concave surface facing the object side, the 5 th lens L5 is a biconvex lens, the 6 th lens L6 is a biconcave lens, and the 7 th lens L7 is a biconvex lens. The 6 th lens L6 is a lens Gp of the present invention, and the 5 th lens L5 is a lens Lp of the present invention. The nth lens is the 7 th lens L7. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 10 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	22.732	1.300	1.85945	40.10
2*	4.749	2.520
					3	-7.495	5.169	1.75035	44.72
4	-9.458	0.200
					5S	0.000	0.803
6*	9.911	6.071	1.58687	59.46
					7*	-14.786	0.200
8	-17.201	3.404	1.49932	81.61
					9	-10.737	0.518
10*	9.813	2.627	1.54845	55.86
					11*	-7.847	0.200
12*	-11.487	1.000	1.65011	23.27
					13*	5.050	1.576
14	6.982	4.812	1.55310	75.52
					15	-134.681	0.400
16	0.000	0.400	1.51986	64.20
					17	0.000	0.900
18	0.000	0.500	1.51986	64.20
					19	0.000	0.300

(various specification values)

F	5.000
		Fno	1.640
θ	63.00

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	-0.3554	-1.10296E-03	1.14301E-05	4.29955E-06	-3.19066E-07
2	-0.0071	-1.21829E-03	8.04817E-05	-2.41827E-05	6.46909E-06
						6	0.0000	1.45424E-04	-4.06361E-05	9.89723E-06	-1.02351E-06
7	0.0000	4.68490E-04	2.46961E-06	2.21946E-06	-2.01211E-07
						10	0.0000	1.90922E-04	3.33920E-05	-6.77897E-06	6.83495E-07
11	0.0000	4.73330E-03	-7.73129E-04	7.82850E-05	-4.62370E-06
						12	0.0000	-8.06959E-04	-1.92911E-04	3.96132E-05	-3.08261E-06
13	0.0000	-5.98800E-03	6.30108E-04	-5.26258E-05	2.90143E-06

Noodle numbering	A12	A14
			1	9.37086E-09	-1.01629E-10
2	-6.18819E-07	2.17766E-08
			6	5.28288E-08	-1.08234E-09
7	1.03609E-08	-1.99251E-10
			10	-3.48786E-08	6.64742E-10
11	1.41934E-07	-1.66528E-09
			12	1.13727E-07	-1.56079E-09
13	-9.57011E-08	1.33647E-09

(focal length of each lens)

	Focal length
		1 st lens	-7.226
2 nd lens	372.616
		No. 3 lens	11.122
No. 4 lens	48.700
		No. 5 lens	8.392
No. 6 lens	-5.270
		No. 7 lens	12.148

[ example 6]

(1) Optical construction

Fig. 11 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 6 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having negative refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having positive refractive power, a 6 th lens L6 having positive refractive power, a 7 th lens L7 having negative refractive power, and an 8 th lens L8 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 3 rd lens L3. An infrared cut filter IRCF is disposed on the image side of the 8 th lens L8.

In the imaging lens, the 1 st group is constituted by the 1 st lens L1 to the 3 rd lens L3, and the 2 nd group is constituted by the 4 th lens L4 to the 8 th lens L8. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a biconcave lens, the 3 rd lens L3 is a positive meniscus lens with a concave surface facing the object side, the 4 th lens L4 is a biconvex lens, the 5 th lens L5 is a positive meniscus lens with a concave surface facing the object side, the 6 th lens L6 is a biconvex lens, the 7 th lens L7 is a biconcave lens, and the 8 th lens L8 is a biconvex lens. The 7 th lens L7 is a lens Gp of the present invention, and the 6 th lens L6 is a lens Lp of the present invention. The nth lens is the 8 th lens L8. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 12 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

(various specification values)

F	5.000
		Fno	1.640
θ	63.000

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	-0.5920	-6.83091E-04	2.55655E-06	4.74550E-06	-3.26150E-07
2	-0.0786	-4.52940E-04	1.13343E-04	-2.65794E-05	6.73867E-06
						8	0.0000	-8.38898E-05	-2.81919E-05	8.92965E-06	-9.61810E-07
9	0.0000	-1.61427E-04	1.83733E-05	9.23439E-07	-1.20354E-07
						12	0.0000	-1.26750E-04	6.91745E-06	-5.94011E-06	6.63327E-07
13	0.0000	4.31635E-03	-7.84601E-04	7.93927E-05	-4.67852E-06
						14	0.0000	-4.29733E-04	-1.84030E-04	3.83980E-05	-3.09891E-06
15	0.0000	-5.42547E-03	6.29469E-04	-5.34283E-05	2.93108E-06

Noodle numbering	A12	A14
			1	9.36771E-09	-1.01629E-10
2	-6.18819E-07	2.17766E-08
			8	5.28288E-08	-1.08234E-09
9	1.03609E-08	-1.99251E-10
			12	-3.48786E-08	6.64742E-10
13	1.41934E-07	-1.66528E-09
			14	1.13727E-07	-1.56079E-09
15	-9.57011E-08	1.33647E-09

(focal length of each lens)

	Focal length
		1 st lens	-10.221
2 nd lens	-12.896
		No. 3 lens	22.420
No. 4 lens	13.614
		No. 5 lens	33.910
No. 6 lens	7.841
		No. 7 lens	-5.166
8 th lens	11.300

[ example 7]

(1) Optical construction

Fig. 13 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 7 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having negative refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having negative refractive power, a 6 th lens L6 having positive refractive power, a 7 th lens L7 having positive refractive power, an 8 th lens L8 having negative refractive power, and a 9 th lens L9 having positive refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 3 rd lens L3. An infrared cut filter IRCF is disposed on the image side of the 9 th lens L9.

In the imaging lens, the 1 st group is constituted by the 1 st lens L1 to the 3 rd lens L3, and the 2 nd group is constituted by the 4 th lens L4 to the 9 th lens L9. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a biconcave lens, the 3 rd lens L3 is a biconvex lens, the 4 th lens L4 is a biconvex lens, the 5 th lens L5 is a negative meniscus lens with a concave surface facing the image side, the 6 th lens L6 is a biconvex lens, the 7 th lens L7 is a biconvex lens, the 8 th lens L8 is a biconcave lens, and the 9 th lens L9 is a biconvex lens. The 8 th lens L8 is a lens Gp of the present invention, and the 7 th lens L7 is a lens Lp of the present invention. The nth lens is the 9 th lens L9. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 14 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

Noodle numbering	r	d	Nd	vd
					1*	22.403	1.300	1.85141	40.10
2*	6.275	2.550
					3	-7.369	0.600	1.62303	58.12
4	11.522	0.724
					5	24.829	5.766	1.74334	49.22
6	-9.419	0.200
					7S	0.000	1.005
8*	9.524	4.102	1.61803	63.39
					9*	-20.377	0.368
10	84.689	2.000	1.67276	32.17
					11	7.707	0.811
12	17.396	2.000	1.49701	81.61
					13	-15.345	0.200
14*	7.941	2.336	1.54475	55.86
					15*	-16.380	0.322
16*	-17.356	0.700	1.63987	23.27
					17*	6.105	1.500
18	7.371	0.900	1.61803	63.39
					19	-100.000	1.597
20	0.000	0.400	1.51682	64.20
					21	0.000	0.700
22	0.000	0.500	1.51682	64.20
					23	0.000	0.500

(various specification values)

F	5.001
		Fno	1.640
θ	63.000

(aspherical surface coefficient)

Noodle numbering	A12	A14
			1	9.36771E-09	-1.01629E-10
2	-6.18819E-07	2.17766E-08
			8	5.28288E-08	-1.08234E-09
9	1.03609E-08	-1.99251E-10
			14	-3.48786E-08	6.64742E-10
15	1.41934E-07	-1.66528E-09
			16	1.13727E-07	-1.56079E-09
17	-9.57011E-08	1.33647E-09

(focal length of each lens)

	Focal length
		1 st lens	-10.633
2 nd lens	-7.127
		No. 3 lens	9.897
No. 4 lens	11.082
		No. 5 lens	-12.736
No. 6 lens	16.744
		No. 7 lens	10.162
8 th lens	-6.977
		9 th lens	11.249

[ example 8]

(1) Optical construction

Fig. 15 is a lens cross-sectional view in infinity focusing of an imaging lens of embodiment 8 according to the present invention. The imaging lens is composed of a 1 st lens L1 having negative refractive power, a 2 nd lens L2 having negative refractive power, a 3 rd lens L3 having positive refractive power, a 4 th lens L4 having positive refractive power, a 5 th lens L5 having negative refractive power, a 6 th lens L6 having positive refractive power, a 7 th lens L7 having positive refractive power, an 8 th lens L8 having negative refractive power, a 9 th lens L9 having positive refractive power, and a 10 th lens L10 having negative refractive power, which are arranged in this order from the object side. When focusing from an infinite-distance object to a close-distance object, all the lenses move along the optical axis toward the object side. The aperture stop S is disposed on the image side of the 3 rd lens L3. An infrared cut filter IRCF is disposed on the image side of the 10 th lens L10.

In the imaging lens, the 1 st group is constituted by the 1 st lens L1 to the 3 rd lens L3, and the 2 nd group is constituted by the 4 th lens L4 to the 10 th lens L10. The 1 st lens L1 is a negative meniscus lens with a concave surface facing the image side, the 2 nd lens L2 is a biconcave lens, the 3 rd lens L3 is a biconvex lens, the 4 th lens L4 is a biconvex lens, the 5 th lens L5 is a biconcave lens, the 6 th lens L6 is a biconvex lens, the 7 th lens L7 is a biconvex lens, the 8 th lens L8 is a biconcave lens, the 9 th lens L9 is a biconvex lens, and the 10 th lens L10 is a negative meniscus lens with a concave surface facing the object side. The 8 th lens L8 is a lens Gp of the present invention, and the 7 th lens L7 is a lens Lp of the present invention. The nth lens is the 10 th lens L10. The lens Gp and the lens Lp are resin lenses, and are glass lenses.

(2) Numerical example

Next, as numerical examples to which specific numerical values are applied in the imaging lens, "lens data", "various specification values", "aspherical coefficients", and "focal lengths of the respective lenses" are shown. Fig. 16 shows a longitudinal aberration diagram in infinity focusing of the imaging lens.

(lens data)

(various specification values)

F	5.000
		Fno	1.640
θ	63.000

(aspherical surface coefficient)

Noodle numbering	k	A4	A6	A8	A10
						1	-6.0439	-4.69873E-04	-5.24473E-07	4.64210E-06	-3.24567E-07
2	-0.0551	2.41911E-04	1.28585E-04	-2.77407E-05	6.91451E-06
						8	0.0000	-4.87395E-05	-2.88226E-05	9.53005E-06	-1.00318E-06
9	0.0000	-2.80812E-04	2.86822E-05	1.86585E-06	-1.90598E-07
						14	0.0000	-9.42254E-04	-8.24074E-06	-4.78607E-06	6.67993E-07
15	0.0000	3.82515E-03	-7.89553E-04	7.88805E-05	-4.67713E-06
						16	0.0000	-3.39389E-04	-1.94959E-04	3.81290E-05	-3.12302E-06
17	0.0000	-6.01218E-03	6.63009E-04	-5.37122E-05	2.95568E-06

(focal length of each lens)

1 st lens	-8.999
		2 nd lens	-7.964
No. 3 lens	8.472
		No. 4 lens	17.170
No. 5 lens	-21.498
		No. 6 lens	12.838
No. 7 lens	11.331
		8 th lens	-7.814
9 th lens	9.336
		10 th lens	-20.000

[ Table 1]

		Example 1	Example 2	Example 3	Example 4
						(1)	f/f2p	-0.212	-0.105	-0.111	-0.102
(2)	ctGA/f	0.657	0.794	0.778	0.846
						(3)	fs/f	2.136	2.707	2.653	2.078
(4)	f×tan(θ)/Yh	2.368	2.421	2.695	2.272
						(5)	Ng1	1.851	1.859	1.856	1.851
(6)	Ng2	1.744	1.764	1.776	1.620
						(7)	Dpp/f	0.040	0.030	0.059	0.106
(8)	Pair×f	0.065	0.076	-0.077	-0.111
						(9)	f1G/f	-2.163	-2.686	-4.196	-6.478
(10)	DD/LL	0.679	0.668	0.579	0.663
						(11)	L/Yh	7.841	7.341	7.930	8.020
(12)	fL/f	2.319	2.694	2.490	-1.175
								Example 5	Example 6	Example 7	Example 8
(1)	f/f2p	-0.102	-0.146	-0.106	-0.098
						(2)	ctGA/f	0.846	0.686	0.607	0.677
(3)	fs/f	2.078	2.737	2.216	3.454
						(4)	f×tan(θ)/Yh	2.272	2.367	2.367	2.367
(5)	Ng1	1.859	1.859	1.851	1.859
						(6)	Ng2	1.750	1.627	1.623	1.627
(7)	Dpp/f	0.106	0.053	0.064	0.070
						(8)	Pair×f	0.066	-0.035	-0.018	-0.033
(9)	f1G/f	-6.478	-2.384	-4.230	-7.396
						(10)	DD/LL	0.802	0.564	0.558	0.569
(11)	L/Yh	8.020	7.839	7.839	7.839
						(12)	fL/f	-1.175	2.273	2.249	-4.059

[ Table 2]

The following results were obtained for the imaging lenses of examples 1 to 3 when the variation of the angle of view at normal temperature, the angle of view at an ambient temperature of 125 ℃, and the angle of view at an ambient temperature of-20 ℃ (80 degree incidence) were obtained. The variation of the angle of view at 125 ℃ is less than + -0.200 DEG, and the variation of the angle of view at-20 DEG is less than + -0.100 deg. In addition, the same applies to the imaging lenses of embodiments 4 to 10 as well as to the range of variation of the angle of view at each temperature. Therefore, it was confirmed that an imaging lens having a small change in the field angle even when the atmospheric temperature greatly changed was obtained. In particular, in the imaging lens according to each embodiment, since the variation in the angle of view is small even in an extremely high temperature environment of 125 ℃, good imaging performance can be obtained even in a severe environment.

[ example 1 ]: angle of view at ambient temperature: 126 degree

Variation of field angle at 125 ℃: +0.185 degree

-variation of field angle at 20 ℃: -0.094 °

[ example 2 ]: angle of view at ambient temperature: 132 degree

Variation of field angle at 125 ℃: -0.013 °

-variation of field angle at 20 ℃: -0.020 °

[ example 3 ]: angle of view at ambient temperature: 132 degree

Variation of field angle at 125 ℃: -0.067 °

-variation of field angle at 20 ℃: -0.020 °

Industrial applicability

The imaging lens according to the present invention includes a resin lens, thereby achieving weight reduction and cost reduction, and suppressing a change in a field angle due to a change in an ambient temperature.

Claims

1. An imaging lens is characterized in that,

the imaging lens is composed of n lenses, the n lenses comprise a 1 st lens with a concave object side and a 2 nd lens with a concave object side which are arranged in sequence from the object side, and an nth lens with positive focal power which is arranged closest to the image side, n is more than or equal to 6 and less than or equal to 10,

when a stop is disposed between the 1 st lens and the n-th lens, the object side of the stop is defined as a 1 st group, and the image side of the stop is defined as a 2 nd group,

the 2 nd group includes lenses Gp having a refractive index N corresponding to the d-line of N < 1.68 and an Abbe number V corresponding to the d-line of 16 < V < 31,

the lens arranged adjacent to the lens Gp is a resin lens Lp,

the imaging lens satisfies the following conditions:

-0.59＜f/fp＜-0.01·····(1)

wherein the content of the first and second substances,

f: the focal length of the imaging lens

fp: the combined focal length of the lens Gp and the lens Lp.

2. An imaging lens is characterized in that,

the imaging lens is composed of n lenses including a 1 st lens and a 2 nd lens which are arranged in order from the object side and have concave surfaces on the image side, and an nth lens arranged closest to the image side, wherein n is 5,

the lens arranged adjacent to the lens Gp is a resin lens Lp,

the imaging lens satisfies the following conditions:

-0.59＜f/fp＜-0.01·····(1)

wherein the content of the first and second substances,

f: the focal length of the imaging lens

fp: the combined focal length of the lens Gp and the lens Lp.

3. The imaging lens according to claim 1 or claim 2,

the 1 st group is composed of 3 or less lenses including the 1 st lens and the 2 nd lens,

the lens disposed closest to the image side of the 1 st group has positive power.

4. Imaging lens according to any one of claim 1 to claim 3,

the following conditional expressions are satisfied:

0.1＜ctGA/f＜1.2·····(2)

wherein the content of the first and second substances,

ctGA: the sum of the central thickness of the lens Gp and the central thickness of the lens Lp.

5. Imaging lens according to any one of claim 1 to claim 4,

a lens having a convex image side is disposed adjacent to the object side of the aperture stop, and a lens having positive refractive power is disposed adjacent to the image side of the aperture stop.

6. Imaging lens according to any one of claim 1 to claim 5,

the following conditional expressions are satisfied:

0.9＜fs/f＜4.5·····(3)

wherein the content of the first and second substances,

fs: a focal length of a lens disposed adjacent to an image side of the stop.

7. Imaging lens according to any one of claim 1 to claim 6,

the following conditional expressions are satisfied:

1.8＜f×tan(θ)/Yh＜3.2·····(4)

wherein the content of the first and second substances,

yh: the maximum image height of the imaging lens

θ: the half field angle of the imaging lens.

8. Imaging lens according to any one of claim 1 to claim 7,

the following conditional expressions are satisfied:

1.8＜Ng1＜2.0·····(5)

wherein the content of the first and second substances,

ng 1: a refractive index of the 1 st lens corresponding to the d-line.

9. Imaging lens according to any one of claim 1 to claim 8,

the following conditional expressions are satisfied:

1.55＜Ng2＜1.89·····(6)

wherein the content of the first and second substances,

ng 2: a refractive index of the 2 nd lens corresponding to the d-line.

10. Imaging lens according to any one of claim 1 to claim 9,

the following conditional expressions are satisfied:

0.01＜Dpp/f＜0.40·····(7)

wherein the content of the first and second substances,

dpp: the lens Gp is spaced from the lens Lp on the optical axis.

11. Imaging lens according to any one of claim 1 to claim 10,

the following conditional expressions are satisfied:

-0.3＜Pair×f＜0.3·····(8)

wherein the content of the first and second substances,

In this case, the amount of the solvent to be used,

n 1: a refractive index corresponding to the d-line of a lens disposed on the object side among the lens Gp and the lens Lp

n 2: a refractive index corresponding to the d-line of a lens arranged on the image side among the lens Gp and the lens Lp

r 1: radius of curvature of object side of the air lens

r 2: a radius of curvature of an image side surface of the air lens.

12. Imaging lens according to any one of claim 1 to claim 11,

at least one glass lens having substantial optical power is disposed on each of the object side and the image side of the lens Gp and the lens Lp adjacent to each other.

13. Imaging lens according to any one of claims 1 to 12,

the lens Gp is a biconcave lens, and the lens Lp is a biconvex lens.

14. Imaging lens according to any one of claims 1 to 13,

the following conditional expressions are satisfied:

-9.0＜f1G/f＜0.0·····(9)

wherein the content of the first and second substances,

f 1G: the focal length of group 1.

15. Imaging lens according to any one of claim 1 to claim 14,

the following conditional expressions are satisfied:

0.40＜DD/LL＜0.95·····(10)

DD: a sum of central thicknesses of the lenses of the 1 st lens to the n-th lens

LL: a distance on an optical axis from an object-side surface of the 1 st lens to an image-side surface of the n-th lens.

16. An imaging device is characterized by comprising:

an imaging lens according to any one of claim 1 to claim 15; and

and an image pickup element that converts an optical image formed by the imaging lens into an electric signal on an image side of the imaging lens.